Disk drive unit is a common information storage device. Referring to FIG. 1a, a conventional disk drive unit 1′ contains a number of rotatable magnetic disks 12′ attached to a spindle motor 13′, and a head stack assembly (HSA) 14′ which is rotatable about an actuator arm axis 16′ for accessing data tracks on the magnetic disks 12′ during seeking. The HSA 14′ contains a set of drive arms 142′ and HGAs 144′ mounted on the ends of the drive arms 142′. Typically, a spindling voice-coil motor (VCM) 18′ is provided for controlling the motion of the drive arm 142′.
Referring to FIGS. 1a and 1b, the HGA 144′ contains a magnetic head 1442′ and a suspension 1443′ supporting the magnetic head 1442′. When the hard disk drive 1′ is on, the spindle motor 13′ will rotate the magnetic disk 12′ at a high speed, and the magnetic head 1442′ will fly above the magnetic disk 12′ due to the air pressure drawn by the rotated magnetic disk 12′. The magnetic head 1442′ moves across the surface of the magnetic disk 12′ in the radius direction under the control of the VCM 18′. With a different track, the magnetic head 1442′ can read data from or write data to the magnetic disk 12′. The suspension 1443′ includes a load beam 1444′, a base plate 1445′, a hinge 1446′ and a flexure 200′, all of which are assembled with each other. The hinge 1446′ has a mounting hole 1446a′ formed thereon to assemble the hinge 1446′ to the base plate 1445′. The flexure 200′ includes a suspension tongue (not shown), and the magnetic head 1442′ is carried on the suspension tongue.
Generally, multiple electrical connection pads are arranged on one end of the flexure 200′ and adapted for connecting to the magnetic head 1442′ by a way of solder joints. The other end of the flexure 200′, also known as flexure tail 220′ (as shown in FIG. 2a), has a number of bonding pads 2264′ disposed thereon and connected to a printed circuit board (PCB) 19′ (as shown in FIG. 1a). Thus, the flexure 200′ serves as the bridge electrically connecting the magnetic head 1442′ and the PCB 19′.
Conventionally, the methods of connecting the flexure tail with the PCB 19′ include soldering jetting process and hot bar process, but the configurations of the flexure tails are different for the two different processes. FIGS. 2a to 2c shows a conventional flexure tail 220′ connected with the PCB 19′ by the way of soldering jetting process, and FIGS. 3a to 3c shows another conventional flexure tail 240′ connected with the PCB 19′ by the way of hot bar process.
Referring to FIGS. 2a to 2c, this conventional flexure tail 220′ (namely soldering jetting flexure tail) contains a stainless steel type (SST) layer 222′, a dielectric layer 224′, a copper layer 226′ and a cover layer 228′. The detailed configuration of the flexure tail 220′ is that the dielectric layer 224′ is sandwiched between the SST layer 222′ and the copper layer 226′, and the cover layer 228′ covers the copper layer 226′. The copper layer 226′ comprises a plurality of conductive traces 2262′ and a plurality of bonding pads 2264′ adapted for connecting with the PCB 19′, the SST layer 222′, the dielectric layer 224′, and the cover layer 228′ are configured with at least a window therein to expose the bonding pads 2264′, wherein a hole 2266′ is disposed at a center position of each bonding pad 2264′. During the soldering jetting process, a front side (as shown in FIG. 2a) of the flexure tail 220′ abuts against the PCB 19′ with the bonding pads 2264′ of the flexure tail 220′ being aligned with a plurality of electrical pads (not shown) of the PCB 19′. Preferably, without regard to the hole 2266′, the shape and size of the bonding pad 2264′ are the same with that of the electrical pad of the PCB 19′. Then, a molten soldering is jetted on a back side (as shown in FIG. 2b) of each bonding pad 2264′, and the molten soldering flows to the front side of the bonding pad 2264′ through the hole 2266′. When the molten soldering become solid, the bonding pad 2264′ can be connected with the electrical pad of the PCB 19′.
Referring to FIGS. 3a to 3c, another conventional flexure tail 240′ (namely hot bar flexure tail) has the same structure with the conventional flexure tail 220′ mentioned-above except the following differences, (1) no hole is disposed at any bonding pad 2464′, (2) a SST bar 2422′ is disposed on the back side of each bonding pad 2464′ (as shown in FIG. 3b). During the hot bar process, a front side (as shown in FIG. 3a) of the flexure tail 240′ abuts against the PCB 19′ with the bonding pads 2464′ of the flexure tail 240′ being aligned with a plurality of electrical pads of the PCB 19′, and each electrical pad is applied with a tin layer. Then, a hot bar (not shown) is connected with the SST bar 2422′ lain on the back side of the bonding pad 2464′, the hot bar is a heat source, and the SST bar 2422′ serves as a thermal conductor, so the bonding pad 2464′ can be heated by the hot bar, and the heat is transferred to the electrical pad of the PCB 19′ that connected to the front side of the bonding pad 2464′. Thus, the tin layer on the electrical pad will be melted. When the hot bar is moved from the SST bar 2422′ or stops supplying heat, the melted tin layer can be solid again, and then the bonding pad 2464′ and electrical pad can be connected together.
In conclusion, some manufactures use soldering jetting process, while others use hot bar process, and different types of processes need different types of flexure tails 220′, 240′, so different types of flexure tails 220′, 240′ must be provided to meet the needs of all manufactures, which would need different machine tools, more space, and more workers to produce. In addition, it is difficult to estimate the exact demand of different types of flexure tails 220′, 240′, which may result in inventory buildups. All of these mentioned-above will increase the manufacturing cost.
Hence, it is desired to provide a flexure, an HGA, and a disk drive unit to overcome the above-mentioned drawbacks.